# Questions tagged [linear-systems]

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### Linear Nastran model not converging

I am running a SOL 101 linear statics FEA. If I fix down the whole geometry it converges. But anything less than around 90% fix down and it will sit there crunching away at the numbers forever. This ...
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### Lyaponuv stability condition of linear systems for homogenous P in V(x) = x^T P x

I am currently learning about using Lyaponuv functions to find Linear Matrix Inequalities (LMIs) as conditions for stability of a linear time invariant system. i.e. $$\dot{x}(t) = Ax(t)$$ is stable ...
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### LQR control effort / control bandwidth relationship

I'm working with a linear system, having given matrices A and B $$A = \left[\begin{array}{cc} 0 & 1 \\ -0.9 & 0 \end{array}\right]$$ $$B = \left[\begin{array}{c} 0 \\ 2 \end{array}\right]$$ ...
I wish to find the polynomials B(s) and A(s) in the following compensator equation: A(s)D(s) + B(s)N(s) = F(s) Given, $$N(s) = s - 2$$ $$D(s) = s^2 - 1$$ $$F(s) = s^2 + 3*s + 4$$ Condition The degree ...